CSS

CSS backface-visibility

#div1 {
  -webkit-backface-visibility: hidden; /* Safari */
  backface-visibility: hidden;
}

#div2 {
  -webkit-backface-visibility: visible; /* Safari */
  backface-visibility: visible;
}

backface-visibility: hidden;

 backface-visibility: hidden;Instead of it being visible, you could hide it. .flip { transform: rotateY(180deg);